Foraging Grounds of Adult Loggerhead Sea Turtles Across the Mediterranean Sea: Key Sites and Hotspots of Risk

Abstract

Delineating priority areas for highly mobile marine megafauna represents a major challenge for conservation biology. To manage such areas, one must understand both their spatial properties (i.e., location, number, extent), and the level of exposure to a number of given pressures. Here, we used a combination of ensemble distribution models, field-based validation methods and a cumulative effect assessment to illustrate key foraging sites and risk hotspots for adult loggerhead sea turtles, Caretta caretta, in the Mediterranean Sea. We found that foraging sites covered about 10% of the neritic zone of the Mediterranean basin. We identified sites which are well recognized by scientists, but also other areas for which our knowledge on the potential importance is limited. The patterns of the habitat use generated by field data validated the accuracy of the distribution model. About one fifth of the foraging areas hosted in the Mediterranean could be considered as hotspots of risk, characterized by high or very high exposure to cumulative pressures. Our results suggest that management and conservation efforts should continue to be held at key, well-known foraging grounds of adult sea turtles (e.g., Northern Adriatic Sea, Tunisian Plateau) but there are several more potential sites (e.g., parts of the Aegean Sea and the Western Mediterranean) which deserve our attention in order to ensure viable populations.